The present invention concerns a bag-in-carton type container which comprises a carton and a flexible inner bag bonded to the inner surface of the carton for storing a fluid inside, and also a fluid level detector for detecting the fluid quantity remained in the container.
A bag-in-carton used as a container for a liquid is usually in the shape of approximately rectangular parallelepiped. The inner bag is bonded to four side surfaces of the carton. The bag-in-carton is generally used as a container for a low-viscosity liquid such as juice or liqueur.
An ink cartridge disclosed in Japanese Patent Publication No. 93/16968 is for use in storing a high-viscosity liquid like an ink and so on. While the high-viscosity liquid is taken out of the cartridge by sucking with a pump and so on, an inner bag deforms according to the sucking.
When the inner bag deforms, the bag pulls a display tape that covers an opening of the cartridge. As the tape is pulled and separated from the opening, an area of the opening that is not covered by the tape changes, so that the amount of the ink contained in the inner bag can be confirmed visually.
Further, a light-emitting device and a light-detecting device electrically detect the state in which the tape covers the opening. When the amount of the ink is below a certain level, this fact is displayed on a display panel.
However, according to the conventional way of detecting the amount of ink, it is required that the opening stated above is formed on the ink cartridge to confirm the amount of the ink.
In the case where the opening is thus formed on the cartridge, the carton may deteriorate in rigidity and be damaged by shocks caused in conveyance and so on.
Further, the electrical detecting of the amount can be conducted only when the ink is below the certain level. Therefore, in such a case where a large amount of printing is conducted by a printer and the printer is controlled by a remote computer, there is some fear that printing stops on complete consumption of the ink. Hence, if the detecting is not conducted before starting of printing, printing duly starts and continues. Further, if the detecting is conducted during printing, the ink may be consumed before completion of printing. This may waste time if an operator is not aware of the situation.
Further, according to the constitution thus stated, the ink cartridge can not be precisely detected to be empty. Since the cartridge emptiness is detected by judging the separation state of the display tape, a display of emptiness can be possible on the printer side when the ink is actually consumed. This deteriorates efficiency in operating the printer.
A generalized printing apparatus does not detect the amount of ink stored in a cartridge. The apparatus detects the diameter of ink-whirl inside the apparatus by measuring the capacitance thereof. When the amount of the ink is not sufficient, supplementary ink is sucked and supplied. When ink-shortage continues for some ten seconds, the apparatus judges that the ink is empty and this is then displayed.
Therefore, even in the case where an operator sets an empty ink cartridge inside the apparatus by mistake, time of some ten seconds is required until the apparatus detects this fault. Consequently, if the apparatus starts to operate in this condition, spoilage sheets may be sent out due to an ink shortage.
Further, type of ink used for printing has been increased recently and also many types of ink cartridge are provided according to the types of the ink. However, said ink cartridges can not detect the types of the ink.